Reuters' published European patent applications EP 399 850, EP 407 026, and EP 411 748 disclose an automated matching system for anonymous trading of foreign currencies (or other financial instruments) in which a single host computer maintains a central data base consisting of all the trading instruments available for trade, credit information, and the various bids and offers that are present throughout the system. The host computer uses the information in its central data base to match active bids and offers (as well as executing any transitory "hit bid" and "take offer" transactions) based on matching criteria which include the gross counterparty credit limit between counterparties to a potential matching transaction, price, and available quantity. To that end, each client site establishes and may subsequently vary or reset a credit limit for each possible counterparty, which is used by the host computer to establish the gross counterparty credit limit for each possible pair of parties and which is equal to the minimum of the remaining credit (initial credit limit less any applicable transactions that have already been executed) from the first party to the second party and from the second party to the first party. The host computer blocks completion of an otherwise eligible matching transaction between a given pair of potential counterparties when the transaction has an associated value in excess of the applicable gross credit limit. In that system, the various client site computers (keystations) merely maintain and display a restricted subset of the information available at the central computer, such as a predetermined number of the best bids and offers, and communicate credit and other transaction oriented information to the host computer for execution. However, in an attempt to preserve the anonymity of the parties, the client sites do not have access to any credit limits set by their possible counterparties, or even to the identification of any other party to a particular transaction until after a transaction has been completed.
Thus, in the known prior art system, confidential counterparty credit limit data is maintained in real time and utilized as part of the trade matching process by a central host computer. As a consequence, each client site has no way to determine, prior to committing to buy or sell at a displayed price from one or more anonymous counterparties, whether it is in fact eligible to respond to any of the bids or offers currently being displayed. The client site is connected to the central host computer by telecommunication lines; the host computer is not under the direct control of the party providing the confidential credit limit data and thus provides potential opportunities for unauthorized access to the credit information, even though the host computer does not utilize the credit information until a match has been found between a Buyer and a Seller.
Consequently, unless he attempts to execute a trade at the best price currently displayed on his screen, a trader using the prior art anonymous matching system has no way of knowing whether he has credit with, and is willing to extend credit to, the anonymous counterparty offering (bidding) the best price currently displayed on his screen and thus whether any attempt to buy or sell at the displayed price will be subsequently invalidated by the system for lack of such credit.